The purpose of the proposed research is to explore new synthetic pathways toward alkene dipeptide peptidomimetics and to explore their conformational properties. The new mimics will include highly substituted alkenes, including mimics of proline-containing dipeptides. The choice of alkene substituents has been guided by molecular modeling. Specifically, the isosteres will be synthesized by nti-SN2' cuprate additions to alkenyl aziridines prepared by asymmetric aza-glycid ester condensations. Subsequently, and extension of this methodology to phosphonate and boronate analogs will be investigated and substituted alkene isostere mimics of the Ala-Ser dipeptide will be incorporated into mimics of the M and R cleavage sites of assemblin, an important regulator of human cytomegalovirus maturation.